This commit adds a target called setup-gotools which will download and
install golint and go vet. A developer who wants to run tests for an
individual component (manager, resourcifier, expandybird) can run `make
test` to run golint, vet, and test and in that directory. On first run,
a developer will want to run `make setup-gotools` so that they have
golint and vet to use locally.
There is a `make test` command in each component because running tests
from the root directory will result in lots of output. Running tests in
individual components will help isolate the tests for the component that
is being modified and result in more clear output.